Improvement in dentistby



@with .ta-tts @anni -ffir g|.

and the impression may be removed without injury.

:arranged and operating substantially as and for tllepurposes set' forth.

EDWARD 0;.sMITH AND DAVID E. WILcoX, or GREENVILEEQNEW YORK.

LettersPate-nt No. 77,773, dated May 12,1868.

IMPROVEMENT IN DENTISTRY.

To AIL-L wvHoM IT MARl CONCERN;

Be it knoivn' that we, EDWARD C. SMITH and- DAVID F. Wincox, both of Greenville, county of Greene, State 'of New York, have invented certain new and useful Improvements inv Dentistry; and we do hereby declare `that the following is a fuljl, clear, and exact description of the same, reference being had-to the accompanying drawings, making a part of this specification, in which- Figure 1 is a perspective view of the impressioncup, with the-air-tubes inserted.,

Figure 2 is a sectional view through the middle of the'cup'aud tubes.

,Figure 3, asection of the tubesand'yalvefrod.

Figure 4,y a view of Valve-rod and smaller tube;- and.

Figures 5, 6and .7, separate views of the variousparts.

T hei'e is, in the practice of dentistry, great difficulty inv removing the plaster, wax, or other materialused in taking impressions from the mouth, after aniimpressiou has been made.4 By the lpressure of the plaster against the surface of the mouth, the air is excluded, aud, in consequence thereof, the atmospheric'pressure n the outside of the plaster is so great as to cause pain to. the patient, and sometimes destroys theimpressionin attempting to remove the material. i

The object of this in'ventiouisto overcome this difficulty by furnishingsl simple device' by which atmospheric air may be introduced between the plasterv andl the surface of the mouth. i i

We successfully accomplish -this by inserting, in the impression-cup, air-tubesjin connection with a valverod and spiral spring, as hereinafter set forth.

By reference to the drawings, it will be seen that g. 1 shows the impressiou-cup with theair-tub'es and. valve-rod V inserted'. i lhe tubeit is passed through' the bottom of the cup-C, and` is intended to come' as far above the bottom of the cup as thc plaster, the top of the'valve-rod V being about evcn'withthe 'upper'.'surface `of the plaster when the impression is aboutl to be made. The tube. t is surrounded with the plaster, andthe top' of the valverod only'xtemainsluucovered. In order that thevalvelro'd may tit closely to the roof of the mouth, and also yield to the pressure of the plaster as the impression is made, the air-tube t ismade' to slide downinto thelarger tube, T, at "the same time compressing-thecoilfspring 8,which placed in the lower .part of the tube T, and rests upon the bottom of the,

cap a. The cap a may t closely on the'tube T, or screw on toit.

In order toykeep the tube t in place, a projectiou,.n, is placed onthe'low'er. end, which runs iu, the slot mm in the side ofthe larger tube T. ,The valve-rod V is perforated in the upper end, as shown in iig. 5,`the opening in the top .connecting with'the-opening .through the body of the -rod. WVheu .the top ofthe valve-rod Vis pressed against the-roof ofthe mouth, air is communicatedthereto through thel tubes tl T. The tube t, fitting closely tothe head of the valve-rod V, prevents the plasterfrom' obstructing the air-holes-in the valve-rod.

` Should the air-holes become obstructed by. the plaster, or otherwise, air may be admitted by pressing up the valve-rod so as tomake an opening between the top of tube t andthe headv of the valve-rod, as shown in iig. 4. The introduction of air between the impression-plaster and vthe surface of the mouth, destroys thesuction,

Having thus described our invention', what we claim,- is"- 1. The introduetionof air between the surface of the moutli'and the material used in taking impressions for Aartificial bases for teeth, by means of air-tubes t, valy'eerod V, and spring AS, substantially as set forth. 2. We claim, in combination with the impressiou-cupQfthe tubes t'T, valve-rod V, and coil-springs, when EDWARD c. SMITH, DAVID VVLCOX Witnesses:

N. D u Bols, 'CHARLES Hnnzoe. 

